Electrical discharge tube



Jan. 6, 1959 w. JACOB! ELECTRICAL DISCHARGE TUBE Filed May 20, 1955 INVENTOR.

Werner Jacob L ELECTRICAL DISCHARGE TUBE Werner Jacobi, Grafelfing, near Munich, Germany, asslgnor to Siemens and Halske Aktiengesellschaft, Mu-

nich and Berlin, Germany, a corporation of Germany Application May 20, 1955, Serial No. 509,949 Claims priority, application Germany September 27, 1949 3 Claims. (Cl. 313-247) This invention relates to an electron tube, which is primarily suitable for amplifying or generating oscillations, for demodulation, etc., of high frequencies.

The circuits using such a tube, for example amplifier circuits, it is desirable in many cases that the lead which carries zero potential be located, as far as possible, on the outside and for direct connection to conductors of zero potential or ground potential. This makes it possible, for instance, to design vacuum tube amplifiers which can be directly connected to co-axial lines, cavity resonators, concentric line resonators or similar devices. It is particularly advantageous to apply the zero potential to the outer conductor of a co-axial line forming a part of such an arrangement.

In a high frequency amplifier, it is furthermore advantageous to employ a cathode follower circuit which provides good isolation between input and output circuits. Connections cannot always be arranged easily in this manner when using conventional vacuum tubes in which the plate and grids are of an essentially cylindrical shape encircling the cathode in the center as the lead to the grid which is at zero potential will be in the center of the tube.

The invention eliminates these difiiculties.

The invention provides leads to the electrodes which are located inside of the anode, for example a grid shaped control electrode, and the lead to the power electrode surrounding the grid, for example to the plate, which cross each other in such a manner that the grid lead makes contact with an annular terminal member; the plate lead terminal is placed in the center of terminal member.

The invention may provide, for instance, three electrode leads for grids and plate crossing and penetrating each other. In many cases it may be appropriate to provide a guide for the electrode leads within the discharge tube. The terminal elements and outside contacts may be constructed so that they are suitable for connection to co-axial lines, cavity resonators, concentric line resonators and similar devices.

The invention will be described more in detail with reference to the accompanying drawing Fig. 1 illustrates the circuit of an amplifier tube according to the invention. The input circuit is a co-axial line where the inner conductor 2 which is connected to the cathode 3 of the discharge tube 4 is placed in the center of the outer conductor 1. The outer conductor 1 is connected to the grid 5. The output circuit is likewise connected with a co-axial line. The plate 6 is connected to the inner conductor 7 of a co-axial line 8.

An example of an embodiment of the invention in its essential parts is schematically illustrated in Fig. 2. A substantially cylindrical plate 9 is shown surrounding grid 10. Cathode 11 with heater 12 are located inside of grid 10. The plate and the grid are connected at Patented Jan. 6, 1959 ice the top by three leads each indicated respectively at, 13, 14, 15 and 16, 17, 18. The grid leads connect with an annular terminal element 19 and the plate leads connect with a central terminal element 20. Numeral 21 indicates an envelope part surrounding and enclosing the electrodes and the leads therefor. Numeral 22 indicates another envelope part extending transversally across the space between the terminal elements 19 and 20 in sealing engagement therewith. The use of three leads for the plate and for the grid, respectively, assures, on the one hand, snfiicient mechanical stability and, on the other hand, provides the chance of keeping the grid-plate capacitance low. The cathode and grid leads at the opposite end of the electrode assembly may be brought out through the bottom wall of the envelope part 21 in customary manner, creating no constructional difficulties at all as the cathode is already placed inside of the grid. Accordingly, the lead for the cathode 11 is extended through the bottom of the envelope part 21 and sealed thereto as shown in Fig. 2; the lead for the grid 10 (not visible in Fig. 2) may be similarly extended through the bottom wall.

Changes may be made within the scope and spirit of the appended claims.

I claim:

1. An electrode structure for use in an electric discharge tube comprising a cathode, a control grid surrounding said cathode, a plate surrounding said grid, a first centrally disposed terminal element for said plate, a second annular terminal element for said grid disposed concentric with said first centrally disposed terminal element for said plate, and means for respectively interconnecting said plate with said first centrally disposed terminal element and said grid with said second annular terminal element, said last named means comprising leads extending in generally radially disposed planes from said plate inwardly and connecting with said first centrally disposed terminal element, and leads extending in generally radially disposed planes from said grid outwardly and connecting with said second annular terminal element.

2. An electrode structure according to claim 1, comprising three leads extending from said plate and connecting with said centrally disposed first terminal element, and three leads extending from said grid and connecting with said second annular terminal element.

3. An electrode structure for use in an electric discharge tube comprising concentrieally arranged electrode elements including a grid and a plate, terminal means disposed at least at one end of said electrode elements comprising a substantially axially centrally disposed terminal member and an annular terminal member disposed concentric thereto, leads extending from one of said electrode elements radially inwardly at an acute angle to said axis and connecting with said centrally disposed terminal member, and leads extending from the other one of said electrode elements radially outwardly at an acute angle to said axis and connecting with said annular terminal member.

References Cited in the file of this patent UNITED STATES PATENTS 2,099,531 Passarge Nov. 16, 1937 2,195,474 Wagener Apr. 2, 1940 2,412,997 Litton Dec. 24, 1946 2,509,906 Clark et al. May 30, 1950 2,707,757 Agule May 3, 1955 

